BirdAnalyst
Species · BCR 10 · BBS 2026 Release · 1966–2025

Brown-headed Cowbird In Northern Rockies

All regionsNorthern RockiesGeneralists

Brown-headed Cowbird in Northern Rockies has increased: up 44% on the route-weighted index since 1970.

+44%Since 1970TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →
221Routes In RegionSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
57YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable SignalsNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

No notable trend signals for Brown-headed Cowbird in Northern Rockies. See the full index history below.

Brown-headed Cowbird In Northern Rockies Population Forecast

If the recent trend holds, Brown-headed Cowbird in Northern Rockies is projected to rise about 45% by 2030 — from 4.6 in 2025 to a central estimate of 6.7 (95% range 3.3–10). A 5-year backtest shows a typical error of ±72.8%, with 40% of held-out values landing inside the 95% band.

+45%Change by 2030TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →
6.7Projected 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
3.3–1095% range95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →
±72.8%Backtest errorBacktest errorTypical error when we hold out the most recent years, forecast them, and compare to what actually happened. Lower means a more trustworthy projection.Full methodology →
If the recent trend holds, Brown-headed Cowbird in Northern Rockies is projected to rise about 45% by 2030 — from 4.6 in 2025 to a central estimate of 6.7 (95% range 3.3–10). A 5-year backtest shows a typical error of ±72.8%, with 40% of held-out values landing inside the 95% band.19682030
Projection of the recent trend (dashed) with 80/95% bands — a projection, not a prediction. Habitat, climate, and land use are not modeled.
YearProjected indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →95% low95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →95% high95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →
20266.63.310
20276.73.310
20286.73.310
20296.73.310
20306.73.310

Routes In Northern Rockies

Routes recording Brown-headed Cowbird in Northern Rockies.
Recent countThe raw number of individuals recorded on this route in its most recent survey year. A single-route tally, not a trend.Full methodology →
Pablo Res.MONTANA562025
CascadeIDAHO551984
SpartaOREGON492025
Church HillMONTANA282025
St MaryMONTANA252008
PolsonMONTANA212025
RandolphUTAH192025
WallowaOREGON182025
MeeteetseWYOMING182025
Muddy CreekMONTANA172015
NewbridgeOREGON172025
WilsonWYOMING172025
BoulderMONTANA162025
BridgeportOREGON162025
Silver CreekOREGON162025
WoodruffUTAH152025
EtheteWYOMING152025
NaplesIDAHO142025
GlenMONTANA132025
Deer ParkWASHINGTON132015
RaynesfordMONTANA122025
Rock RiverWYOMING122022
AugustaMONTANA112025
EllistonMONTANA112025
LimaMONTANA112025

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.